1. Technical Field
The present invention relates to a manufacturing method of a semiconductor device, a semiconductor device, a circuit board, an electro-optic device, and an electronic apparatus.
2. Related Art
In circuit boards, liquid crystal displays, and the like mounted on various types of electronic apparatuses, various techniques to mount electronic components such as semiconductor integrated circuits (ICs) thereon have been used. On the liquid crystal display, for example, an integrated circuit (IC) chip for driving a liquid crystal panel is mounted. The IC chip is sometimes mounted directly on a glass substrate constituting the liquid crystal panel, and is sometimes mounted on a flexible printed circuit (FPC) board mounted on the liquid crystal panel. The former mounting structure is referred to as a chip on glass (COG) structure, and the latter mounting structure as a chip on FPC (COF) structure.
There is a technique of locating an elastic body between an IC chip and the wiring at the side of a substrate in mounting the IC chip. As examples thereof, a method in which an anisotropic conductive film (ACF) containing conductive particles dispersed in a thermosetting resin is placed between electrode terminals, a method of using a bump electrode having elasticity, and so on are known.
In the method of using a bump electrode having elasticity, for example, a resin projection is formed on the active surface of an IC chip and then a conductive film is formed on a surface of the resin projection. A bump electrode is thereby made (e.g. refer to JP-A-2-272737, which is an example of related art). A conductive film on the surface of the bump electrode is electrically connected to an electrode terminal of the IC chip. By pressing the bump electrode against a terminal of the substrate, elastic deformation occurs on the resin projection constituting the bump electrode. By fixing the IC chip to the substrate with a thermosetting resin in this state, conductive contact through the bump electrode is maintained even if the thermosetting resin thermally expands due to a temperature change.
In general, the resin projection constituting the bump electrode is formed by a photolithography method. Namely, a photoresist is applied onto a substrate by using a spin coating technique and the photoresist film is exposed to light through a mask for patterning, is then developed by using a developing fluid, and is hardened by baking at high temperature. The conductive film constituting the bump electrode is typically formed by a soldering method.
There have been demands in electronic components such as IC chips for stabilizing quality as well as reducing cost. Establishing a manufacturing method to meet such demands is desired.